Sandhill dunnart description

Also known as the large desert marsupial-mouse, the sandhill dunnart (Sminthopsis psammophila) is not in fact a mouse, but a medium-sized carnivorous marsupial(4). It is one of the largest dunnart (Sminthopsis) species, and like other dunnarts it is characterised by its long, pointed snout, large eyes and ears, and relatively long, slender hind feet (5).

The sandhill dunnart has grey to buff fur, interspersed with darker hairs, while the fur on its belly and feet is whitish and its face is buff-coloured, with a darker triangle on the forehead and crown. The eyes of the sandhill dunnart are dark (4).

The tail of the sandhill dunnart is longer than its head and body, and is grey above and darker below (4). This species is distinguished from other dunnarts both by its larger size and by the distinctive crest of stiff black hairs along the underside of its tail, near the tip (4)(5).

Related species

Sandhill dunnart biology

Like other dunnarts, the sandhill dunnart is an insectivore. It has a generalist, opportunistic diet, taking a variety of invertebrates including ants, beetles, spiders, grasshoppers and termites. Occasionally, this species has also been known to eat small reptiles (5).

The sandhill dunnarts that occur in Eyre Peninsula nest in the hollow parts of spinifex hummocks that are created when the plants start to die off at the centre. The dunnart accesses these hollow areas by leaping up onto the hummock, climbing over the top of the plant and down into the centre, where it builds a circular space (5). Enclosed within the dense, prickly, needle-like leaves, the sandhill dunnart is relatively safe from predators, and is also provided with a fairly stable environment where it is protected against extremes of temperature (5)(6).

In the Great Victoria Desert, the sandhill dunnart lives within burrows that it digs beneath larger spinifex hummocks. The burrows range from 12 to 110 centimetres in length and are up to 46 centimetres deep, and like spinifex nests they provide shelter against extremes of temperature and humidity. The use of burrows therefore allows the sandhill dunnart to save energy and water in its desert environment (5)(6). On the Eyre Peninsula, adult female sandhill dunnarts occasionally dig burrows that spiral down from within a spinifex clump and end in a chamber containing nesting material like bark and leaves. However, these burrows appear to be only used for rearing young (5).

Male sandhill dunnarts use a much greater variety of nest sites than females, and have been found living not only in spinifex, but also in small burrows dug between spinifex clumps, in hollow logs, and in burrows dug by other species (5).

Mating in the sandhill dunnart appears to take place mainly in September (1)(5), although in captivity the female sandhill dunnart has been reported to be receptive for just a short period between June and July (7). The sandhill dunnart is likely to produce a single litter each year, but if conditions are favourable a second litter may potentially be produced. In some areas, young dunnarts have been recorded at other times of year, suggesting that the breeding period may be broader than currently thought (5). The interval between mating and the birth of the litter ranges from 16 to 19 days (7).

The female sandhill dunnart gives birth to a litter of four to eight poorly developed young, although not all of the young are likely to survive to weaning. For the first few weeks of their life, the young sandhill dunnarts stay in the female’s pouch, each one remaining permanently attached to a teat. By 27 days after birth, the young are large enough that they can no longer by fully enclosed within the pouch, and by 64 days old they are too large to stay in the pouch. At this stage, the female leaves the young in the nest or carries them around on her back (7).

By about December or January (5), at around 76 days old, the young sandhill dunnarts are weaned and start to eat insects that the female brings to them within the nest (7). Both the male and female sandhill dunnart reach reproductive maturity in their first year of life (5)(7).

Sandhill dunnart range

The first specimen of the sandhill dunnart was collected in the Northern Territory of Australia in the late 19th century. However, despite considerable survey efforts, this species has not been sighted in the Northern Territory since, and is likely to have become extinct from the region (1)(4)(5).

Currently, the sandhill dunnart is only known to occur in Eyre Peninsula in South Australia and in the southern Great Victoria Desert of South Australia and Western Australia (1)(4)(5). This poorly known marsupial appears to be patchily distributed, with its populations separated by large distances (5).

Species with a similar range

Sandhill dunnart habitat

The sandhill dunnart inhabits sandy areas in arid and semi-arid regions (5). Its habitat on Eyre Peninsula consists of sand ridges covered by spinifex hummocks (Triodia species) and mallee-broombrush shrub, while in the Great Victoria Desert it occupies sand plains and sand dunes covered in low, open woodland with a shrub understorey and hummocks of spinifex grass (4).

This species appears to have quite specific habitat needs, being dependent on large spinifex hummocks for nest sites. The specific maturity and structure of these hummocks is related to the history of fires in an area, and is believed to govern the distribution and abundance of sandhill dunnart populations. By 20 to 30 years after a fire, mallee trees start to shade out the spinifex undergrowth, making the habitat no longer suitable for the sandhill dunnart (5).

Populations of the sandhill dunnart in the Great Victoria Desert also use spinifex habitats, but are less dependent on them as they dig burrows for shelter and nesting, instead of using the spinifex itself (5).

Sandhill dunnart status

Sandhill dunnart threats

The sandhill dunnart occupies a relatively small area and occurs at only six known locations (1). The likely extinction of the sandhill dunnart from the Northern Territory corresponds to a reduction of over 50 percent in its overall range (5), and its distribution, populations and habitat are continuing to decline (1). There are now believed to be fewer than 2,500 mature sandhill dunnarts left in the wild, and over recent years its total population has decreased by over 20 percent (1).

Although the exact causes of the decline in this species are not known with certainty, it is likely to be under threat from predation by introduced species such as foxes and cats, as well as from habitat degradation due to livestock grazing and inappropriate fire regimes (1)(4).

While there has been little direct evidence of severe predation of the sandhill dunnart by foxes and cats, these introduced predators have caused widespread declines in similarly sized native mammals in Australia, and are likely to represent an ongoing threat to the sandhill dunnart (5).

Changed fire regimes are also recognised as a major threat to this species, due to its dependence on large spinifex hummocks of a particular age and structure, which are produced by a specific pattern of burning. In addition, land clearance for agriculture at Eyre Peninsula has resulted in a major reduction in suitable habitat for the sandhill dunnart, with only 43 percent of the area’s original vegetation remaining, in heavily fragmented and isolated patches (5).

Sandhill dunnart conservation

The sandhill dunnart is listed as ‘endangered’ under the Environment Protection and Biodiversity Conservation Act 1999, which provides a framework for the protection and management of Australian wildlife (5). This species is also listed on Appendix I of the Convention on International Trade in Endangered Species (CITES), which bans any international trade in the sandhill dunnart (3).

This little-known marsupial is also afforded some protection within a number of reserves, such as the Yellabinna Wilderness Protection Area in South Australia and the Queen Victoria Spring Nature Reserve in the Great Victoria Desert (1). However, greater habitat protection is needed in Eyre Peninsula, where much of this species’ habitat has been cleared for agriculture or is leased for grazing (5).

A national recovery plan was published for the sandhill dunnart in 2001. This listed a number of actions to aid in the recovery of the sandhill dunnart, including preventing further habitat clearance, conducting surveys in areas likely to support the species, implementing monitoring programmes for key populations, and conducting research on captive individuals to increase understanding of this species’ reproductive biology. Experimental burns were also recommended to encourage the growth of suitable spinifex habitat (5).

At Perth Zoo, a captive breeding programme has recently been established for the sandhill dunnart, and has resulted in the successful production of some young. This programme is allowing the reproduction of this species to be investigated (7).

Surveys for the sandhill dunnart are ongoing in parts of the Great Victoria Desert (1), and further surveys have been recommended in the Northern Territory, to determine whether the species still occurs in this region (4). Further research is also needed to better understand the habitat requirements and biology of the sandhill dunnart and to further investigate the threats to this rare marsupial(1)(5).

Glossary

Carnivorous marsupial

A marsupial in the order Dasyuromorphia, a group which includes the quolls, dunnarts, numbat, Tasmanian devil and thylacine. Most members of the group are specialised for an insectivorous (insect-eating) or carnivorous (meat-eating) diet.

A diverse group of mammals characterised by their reproduction, in which gestation is very short, and the female typically has a pouch (marsupium) in which the young are raised. When born, the tiny young crawls to the mother’s teats, where it attaches and stays for a variable amount of time, whilst it continues to develop. Marsupials also differ from placental mammals in their dentition.

Churchill, S. (2001) Survey and Ecological Study of the Sandhill Dunnart, Sminthopsis psammophila, at Eyre Peninsula and the Great Victoria Desert. Department for the Environment and Heritage, South Australia.

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